Many of fluid foods such as fruit juice, UHT (ultrahigh treatment) milk, wine, tomato sauce or the like are dispensed with packed in packaging containers for fluid foods, which are made of aseptic package materials.
Typical examples of packaging containers for such fluid foods, are well-known parallelepiped (brick shape) paper containers and roof-shaped paper containers for liquid foods or fluid foods. These paper containers are formed by folding and sealing laminated packaging materials. This packaging material has a multilayer structure including a layer of fiber material, for example paper, coated on either side with heat-sealing plastic material such as polyethylene. Also, in the case of an aseptic paper container for long storage such as with UHT milk, the packaging material includes a layer of oxygen barrier material, for example defined by aluminum foil, which is superposed on the layer of heat-sealing plastic material, and additionally overlaid with a layer of other heat-sealing plastic material forming the inner surface of the packaging, contacting finally with the foods.
The packaging container, in the above described form, for fluid foods generally comprises a pluggable opening device in order to pour the liquid content out. Such an opening device substantially includes a hole forming an opening in a container wall, a frame fitted to a perforation or a cutting-off portion, and a cap.
An outstanding method fitting the opening device directly to a pre-laminated hole where the laminate film is attached to the perforation in the container wall and the packaging container fitted the opening device thereto are described in, for example, Japanese Patent Laid-Open No. 2001-72008.
The brick-shaped (parallelepiped) packaging container is formed into a final shape container 14 of brick shape illustrated for example in FIG. 8 by the following steps, i.e., in a filling machine illustrated for example in FIGS, forming a roll of the web-shaped packaging material 1 with pleat lines, made of fibrous substrate (for example, paper etc.)/plastics laminate, adhering a sealing tape on one end in the longitudinal direction by a applicator 3, forming the material into a tube shape by a forming roll 6 and a longitudinal line sealing unit 8, filling the content in the packaging material formed in a tube shape through a filling pipe 7, transversely sealing the tube-shaped packaging material in the transverse direction by a transverse sealing unit 10, 11, cutting the material at fixed spacing at an individual container, forming a primary shape container 13 with a cushion form or a pillow form, and folding flaps along the pleat lines by a final forming unit 15.
As illustrated in FIG. 6, a packaging material 1 for one container of the web-shaped container material with pleat lines comprises a longitudinal sealing region 26 for longitudinal sealing, a transverse sealing region 23 sealing the tube-shaped packaging material in the transverse direction, a side panel 21 forming a container wall, panels 20a, 22a forming the top part of the container, panels 20b, 22b forming the base part of the container, and panels forming a flap 24 adhered to the side wall or the base part by being folded wherein pleat lines such as 24a, 25a, 25c are formed at the boundary of these panels.
FIGS. 7 (a) (b) (c) illustrate appearances in which the primary shape container 13 is folded along pleat line, formed into the final shape container 14 of the brick shape as shown in FIG. 8, by folding the flap 24. (a) The primary shape container 13 having the front container wall 22, the side-wall 21, the rear container wall 20, the container wall 22a corresponding to the top part, the container wall 22b, 20b corresponding to the bottom part, the transverse sealing part 23 and the longitudinal sealing part 26 is formed. (b) Then, it is folded along pleat line and folding edges (flaps) 24, 25 and a fin 23 for transverse seal are protruded. (c) Finally, the fin 23 for transverse seal is folded, the flap 24 is adhered to the side container wall 21 along the pleat line 24a, the flap 25 is adhered to the bottom container wall along the pleat line 25c. 
In roof-shaped paper packaging containers, the paper packaging material is cut into a predetermined shape, blanks sealed in the container lengthwise direction are formed, after the bottom of the blanks is sealed in a filling machine, cows milk, juice, or other drinks are packed from a top opening, the upper part is sealed, and the product container is obtained. In such packaging materials, the appearance design of a packaging container product is printed on the surface.
As for the roof-shaped paper packaging container, a paper container of which large-sized spout is fitted on a wide roof portion on one side thereof is proposed. (Japanese Patent Laid-Open Nos. 1999-91792 and 1999-236027 etc.)
However, when a shed roof shape of one roof is formed from the roof shape (gable shape) by folding the top seal fin, folding portions are further excessively folded inward, it causes an increase of a tensile or compression stress, thus remarkably reduces the strength characteristics of the paper container.
To the contrary, in a paper container obtained from the web-shaped packaging material described above, a paper container which is not a brick shape, where a folding piece formed by shaping the top part is folded onto a side wall surface, and the top part is formed into a shed roof shape, is proposed. (International Patent Publication WO02/10020).
This enables the paper container to maintain strength characteristics thereof by reducing the tensile or compressive stress and to fit a large-sized spout and a cap to the top part.
There is a difficulty in fitting a large-sized spout to brick-shaped (parallelepiped) packaging containers.
On the other hand, as for roof-shaped paper packaging containers, in the above described container having the tilted surface on the above described conventional top part, a large-sized spout can be fitted to the one side with a wide roof portion. However, when a shed roof shape of one roof is formed from the gable shape by folding the top seal fin, folding portions are further excessively folded inward, it causes an increase of a tensile or compression stress, thus remarkably reduces the strength characteristics of the paper container.
In paper containers of which top part is formed in a shed roof shape, a folding piece (flap) formed by shaping the top part is folded onto the side wall, the tip portion of the top part protrudes at a sharp edge, thus the portion is subject to much of the mechanical stress through manufacturing process, distribution process, and consumption process.
In addition, a conventional pouring plug provided in the above described container having the tilted surface on the top part has a structure in which a bottom portion of a cap adhered to APLH (Area for pre-laminated hole) is pulled up while rotating to form an opening when the cap is opened along the thread from the pouring spout by twisting APLH off. There is, however, a disadvantage that a portion of the lower layer happens to remain on the container side, while only the upper layer adhered to the cap is torn off, if the adhesion between each layer is not sufficient due to the multilayer structure of APLF of the laminate.
Further, there may incur a disadvantage in that fibrous dross remains on the cutting (fractured) surface because a plurality of polyolefin layers consisting of APLH laminate elongates by APLH being twisted off.
Furthermore, air gaps are easily generated in the section of the hole forming an opening of the container wall and in the section of the perforation. Therefore, there is a necessity to reduce a risk that the liquid content penetrates into the section of the container wall when cutting APLH laminate of the proximity to the air gaps.